How can I tell if a given git tag is annotated or lightweight?

Question

I type git tag and it lists my current tags:

1.2.3
1.2.4

How can I determine which of these is annotated, and which is lightweight?

Answer 1

git for-each-ref tells you what each ref is to by default, its id and its type. To restrict it to just tags, do git for-each-ref refs/tags.

[T]he output has three fields: The hash of an object, the type of the object, and the name in refs/tags that refers to the object. A so-called "lightweight" tag is a name in refs/tags that refers to a commit¹ object. An "annotated" tag is a name in refs/tags that refers to a tag object.

- Solomon Slow (in the comments)

Here is an example:

$ git for-each-ref refs/tags                                           
902fa933e4a9d018574cbb7b5783a130338b47b8 commit refs/tags/v1.0-light
1f486472ccac3250c19235d843d196a3a7fbd78b tag    refs/tags/v1.1-annot
fd3cf147ac6b0bb9da13ae2fb2b73122b919a036 commit refs/tags/v1.2-light

with some format:

$ git for-each-ref \
  --format="%(if:equals=tag)%(objecttype)%(then)a %(else)%(if:equals=blob)%(objecttype)%(then)b %(else)  %(end)%(end)%(align:20,right)%(refname:short)%09%(objectname:short)%(end)%09%(if:equals=tag)%(objecttype)%(then)@%(object) %(contents:subject)%(else)%(end)" \
  --sort=taggerdate \
  refs/tags

    v1.2-light  fd3cf14 
b       forsam  633de05 
a   v1.1-annot  1f48647 @1e25186bcf26d260754b6ebf6b236e92eeadc69b annotation comment
    v1.0-light  902fa93

To do this for just one ref, you can use git cat-file -t on the local ref, to continue the example:

$ git cat-file -t v1.0-light
commit
$ git cat-file -t v1.1-annot
tag

---

^{¹ tags can refer to any Git object, if you want a buddy to fetch just one file and your repo's got a git server, you can git tag forsam :that.file and Sam can fetch it and show it. Most of the convenience commands don't know what to do with tagged blobs or trees, but the core commands like update-index and such do}

Answer 2

The git show-ref -d --tags command sort of does it, since lightweight tags occur once in the output, and annotated tags occur twice. Also, only annotated tags include the "^{}" dereference operator in the output.

588e9261795ec6dda4bd0a881cf1a86848e3d975 refs/tags/1.2.3
7fe2caaed1b02bb6dae0305c5c0f2592e7080a7a refs/tags/1.2.4
588e9261795ec6dda4bd0a881cf1a86848e3d975 refs/tags/1.2.4^{}

And that output can than be massaged with the unix sort, sed, cut, and uniq commands to make the output more readable:

git show-ref -d --tags       | 
cut -b 42-                   | # to remove the commit-id
sort                         |
sed 's/\^{}//'               | # remove ^{} markings
uniq -c                      | # count identical lines
sed 's/2\ refs\/tags\// a /' | # 2 identicals = annotated
sed 's/1\ refs\/tags\//lw /'   

For my original repo (from my question) it outputs this:

  lw 1.2.3
   a 1.2.4

(e.g., 1.2.3 was "lightweight" and "1.2.4" was annotated).

Answer 3

Get the tag name (say foo) and then do a git cat-file -t foo. If it's an an annotated tag, cat-file will tell you that it's a "tag". If it's a simple tag, cat-file will tell you that it's a "commit".

Update: As oxymoron said in his comment, git show works too but it gives you more information than just what kind of tag it is.

Answer 4

Please try using git describe

https://git-scm.com/docs/git-describe

By default (without --all or --tags) git describe only shows annotated tags.

Answer 5

In case someone is interested in checking a single tag, you can just do git show <tag-name> and if the tag is lightweight, the output will look exactly like for a regular commit:

commit <hash> (<tags>, <branches>)
Author: John Doe <john@doe.com>
Date:   Wed Apr 12 22:29:20 2023 +0200

The message of the actual commit...

But if it is annotated, the output will start like below, followed by the commit info.

tag <tag-name>
Tagger: John Doe <john@doe.com>
Date:   Wed Apr 12 22:29:20 2023 +0200

The message of the annotated tag...